Hypodermic syringe



Jan. 22, 1957 J. J. MISKEL 2,778,360

HYPODERMIC SYRINGE Filed May 9. 1955 2 Sheets-Sheet 1 FIG.I

FIG-.2

INVEN TOR. JOHN J. M/SKEL H/S ATTORNEYS Jan. 22, 1957 j J WSKEL 2,778,360

HYPODERMIC SYRINGE Filed May 9, 1955 2 Sheets-Sheet 2 FIG 6 INVENTOR.

JOHN J. M/SKEL w/mg HIS ATTORNEYS United States Patent HYPDDERMIC SYRINGEI John J. Miskel, Brooklyn, N. Y., assignor to Chas; Pfizer & Co., Inc, New York, N. Y., a .corporah'on of Delaware Application May 9, 1955, Serial No. 506,913

7 Claims. (Cl. 128218) This invention relates to ahypodermic. syringe, and

more particularly, to an improved hypodermic syringe which maintains a drug or medicament in sealed relationship from the solvent or diluent with which his to be admixed immediately pricrto injection;

In the preparation of injectable forms'of drugs, such as antibiotics, vitamins, hormones, and the like, it is common practice to incorporate the drug into aliquid diluent or'solvent, such as water, and: market a 'suspension'or solution thereof in disposable cartridges equipped for injection, or in vials or bottles from which syringes are filled. stability, since many drugs tend to deteriorate upon aging, particularly in aqueous solutions. Moreover, certain suspensions tend to solidify or form sludge-like deposits on storagefor any period of. time, makingzthem difiicult-or impossible to resuspend or syringe through the usual needles employed for-that purpose.

It was primarily to' meet this problem: that the-bypass? syringe was developed. 111' thistype of'syringe the medicament is generally separated from-tho. solventordiluent'in-which it is tobe dissolved or-suspended; by meansv of a .movable, resilient barrier: or. plungen which acts as avalve' to control .the flow-of diluentthereabout. Upon actuation of the plunger, the. flow of diluent is gen erally directed around the. barrier through a by-passcritself impervious to: moisture, resulting; in: a. certain;

amount of VQPOE. transmission-througlrthezmasst Thus, a certain amount of solvenr' or'mois'ture inevitablyireaches the: solidmedicament and: causes: the same" to; cmreup and/ordeten'ora e; in. many instances: the medicament which:has thus been prematurely exposed tor-solvent: is;

dificultito'suspend. or dissolve llillthfii solvent when it is desired to :prepare. a. mixture ofithe two forinjectionxpur poses; While other attempts, have. been made to soh'e. thistproblem, no satisfactory solution'has:inrthe' past been advancedawhichis medically, mechanically and economically practicable.

Accordingly, one-cf ti aprincipal ob'jects of: this ice vention'is to-provide anximprovedhypodermi'c syringeof.

a novel type which offers a practical solution tothe aforesaid. problems. Another object is to provide; a.dual'.compartment-cartridge for-a hypodermic syringe. A further object ofithis invention is-to providean' improvedrmeans for separating a solid medicament from-asolyentaor, liq.

uid diluent. andfor maintaining. a: solvent-impervious barrier between the two. Another object of this invention is toprovidean improved needleassemblywhichis.

especially adapted, forzuse. with a dual compartmentcar-- tridgeofthe-character described. Other. objects andadvantages of the invention will'becomeapparent from-the description and claims; which follow.

In many cases this creates serious problems in Having broadly disclosed the invention, reference. will now be made to the accompanying drawings, specifically setting forth preferred forms of the invention, in which:

Fig. 1 is a longitudinal view, partly in section, of one form of improved hypodermic syringe of this invention with the componentparts positioned for mixing of a diluent with a medicament.

Fig, 2 is a sectional view along the axial center line of.

a needle suitable for use in the device of Fig. l, illustrating one form of filter which may be constructed therein.

Fig. 3 is a longitudinal View, partly in section, showing the needle of Fig. 2 operatively attached to the syringe. of Fig. 1, after mixing the medicament and diluent,

therein.

Fig. 4 is an enlarged sectional view'ofa preferred plunger employed in accordance with the present inven-v tion.

Fig. 5 is a longitudinal view, partly in section, of a hypodermic syringe constructed according to the present invention, showing a preferred form or" cartridge and. needle assembly which may be employed therein.

Fig. 6 is an enlarged sectional view of the preferred.

needle. assembly of Fig. 5.

Fig. 7 is a longitudinal View, in section, showing an:

other embodiment of a stopper, modified by theaddition.

of 'a filter thereto.

Fig. 8 illustrates still. another form of stopper. andfih. ter1which may be employed inv the present invention.

Referring now to Fig. l of the drawings, showing one form ofsyringe constructed in accordance with this in.- vention, 1 is a hypodermic syringe or casing, which. may be of conventional design for receiving a disposable ampule or cartridge containing a medicament and liquid diluent in sealed relationship from one another. The casing of'the syringe is preferably provided 'with a pivoted casing carries a double pointed'needle 1'13, as'shown in Figs. Zand 3.

Cartridge ill is divided into two' compartments by a frangible membrane 15, preferably-composedof glass, for thepurpose of maintainin a hermeticsealbetween the drymedicament M and'the liquid'diluentD carried" carries a recirocable lunver l7'which formsa-closureforacontaining the liquid diluent between tliesarne and membrane The other end of cartridge ll'carries readily perforable seal 19, shown in- Figs. 1 andlasadiaphragm, advantageously constructed ofa resilient elastomeric material, such asrubber. Th'usdiaphragm is retained'cn the cartridge by means of a hermetically sealed member 21 which overlies the face of the diaphra-gml9 and compresses the same against the neck of the cartridge as by crimping the seal behindthe annular neck ofi the vialin the manner indicated. The closure Cap or seal preferably takes the form of a-cylindrical, cup-like, metallic ferrule of a noncorrosive material such asaluminum, and is adaptedto be secured over the diaphragm 7.9:bysspinning the extended peripheral edgeof the forrule into tight contact with the reduced portion of the vial= neck. The ferrule includes a central aperture 23 which is adapted'to be aligned so as to accommodate the needle. in a manner to be. more fully described. The compartmenhformedbyi the. seal. andsmembrane 15 is adapted;

to contain a dry medicament, preferably in the form of a powder, which is mixed with the liquid diluent upon actuation of plunger 17.

Frangible membrane 15 is so constructed as to be ruptured by the hydrostatic pressure of the liquid diluent within the cartridge upon advancement of plunger l7 toward the membrane, thereby compressing the diluent contained therebctween. The membrane is therefore designed to rupture under normal operating conditions, when pressures of say approximately 16 to 120 pounds per square inch are exerted thereagainsi- To accomplish this, the membrane should generally be relatively thin, an average thickness of from about 50 to 200 microns being satisfactory for most purposes. A thickness of approximately 100 microns is preferred for optimum results when the membrane is constructed of glass. However, it will be appreciated that the thickness of the membrane will vary somewhat with the materials of construction and other factors, such as heat treatment and the like.

Membrane 15 may be constructed inseveral ways. For example, the cartridge may be formed from two sections, one section containing the thin membrane which effectively forms an end wall thereof. The other section, open at both ends, may then be fused to the section containing the end wall in such a manner as to produce the cartridge shown in Figs. 1 and 3. The membrane may also be formed by inserting the same into an open ended cartridge to the desired depth, by suitable means such as a piston, and fusing or otherwise affixing the same to the inner Walls of the cartridge. Thus, it may be secured by applying heat to the outer periphery of the cartridge at the point where the membrane is to be situated. Care should be taken to avoid distortion of the cartridge and/or an accumulation of glass at the point of fusion, if the most advantageous results are to be obtained. The membrane is preferably positioned within the cartridge at a distance from the plunger 17 of approximately one-half to two-thirds of the normal stroke of the plunger. Thus, plunger 17 will ordinarily pass the area of the ruptured membrane during operation of the device.

The needle 13 of Figs. 2 and 3 is comprised of a sharpened cannula 25 which serves as the tissue piercing end and which is carried on a hollow cylindrical hub 27 provided with an area of reduced cross section 31 adapted for threaded attachment to the end wall 32 of the syringe casing 1, as shown in Fig. 3. The inside of hub 27 is provided with a filter 33 for preventing glass particles from passing from the ruptured membrane 15 through the cannula 2.5 and into the patient receiving the injection. Filter 33 advantageously takes the form of a screen of fine size, say from about 100 to 600 mesh, and preferably 200 to 400 mesh, depending upon the particular material to be dispensed therethrough. Alternatively, a microporous stainless steel filter may be employed where the material to be filtered is composed of particles below approximately 10 microns in size. Such filters may range in thickness from to 2 8 inch, the average pore diameter varying from about to 35 microns. The filter not only serves to remove any objectionable glass particles from the stream of injectable fluid, but also it prevents any clumps or large solids present in the final suspension or solution from passing into the cannula 25. Filter 33 may be retained in hub 27 by any suitable means such as friction and the like.

The reduced area 31 of the needle hub in turn carries therewithin a small plug 35 having a central passage 37 therethrough for receiving a cartridge piercing needle 39. the plug 35 is secured to hub 27 by any suitable means, as by threaded staked or force fit. This construction facilitates rapid discharge of the cartridge and assists filter 33 in preventing objectionable glass particles from passing into cannula 25. Thus, after membrane 15 is ruptured by the hydrostatic pressure exerted through plunger 17, few glass particles find their way through the 4 cartridge piercing needle 39, and those that may do so are effectively blockedby filter 33. In this connection, it should be noted that few fine particles are formed when membrane. 15 is ruptured, most of the particles being at least 4;" in diameter. However, these do not adversely affect the operation of the syringe in any way.

A preferred form of plunger is more particularly shown I in Fig. This consists of a body portion 17 composed of a resilient elastomeric material, such as rubber, carryiug a threaded stud 14 for secure attachment of plunger rd 7 thereto. The area surrounding stud 14 is provided with a recess 16 for receiving the end of rod 7. The other face ofplunger 17 is also recessed at 18 for receiving the end of cartridge-piercing needle 39. To gether, these recesses increase the effective stroke of the plunger Within the cartridge 11. A plurality of continuous circumferential ribs 2d are provided about the outer periphery of the plunger to facilitate slidable movement thereof and to prevent leakage during actuation of the plunger. At least 3, and preferably 4, of these ribs are employed in order to obviate leakage as the plunger is forced past the region of membrane 15. While this membrane is designed to break from the inner walls of cartridge 11 as cleanly as possible. an uneven surface may occasionally occur. This can readily cause leakage and poor performance with ordinary plungers, but the provision of a plurality of ribs as indicated maintains an effective seal as the plunger is advanced past the area occupied by the membrane.

The preferred method of operating the syringe of Figs. 1 and 3 is as follows. A sealed cartridge provided with the necessary liquid diluent D separated from the medicament M by membrane 15, is introduced through the syringe casing to the position as shown in Fig. 1, the needle not yet being affixed to the barrel. Plunger rod 7 is then attached to plunger 17 in the usual manner and the plunger isadvanced by exerting pressure on the thumb piece 8 of the plunger rod. This compresses the diluent D within cartridge 11, causing it to rupture membrane 15 and permitting the diluent to contact the medicament M. The entire device is then briefly shaken until all of the medicament is in suspension or solution, the time of shaking varying ofcourse with the particular medicament and diluent or solvent system involved. Thereafter, the needle 13 is attached to the end wall 32 of the casing, forcing the cartridge piercing end 39 through diaphragm 19 of the cartridge seal and exposing the needle to the contents of the cartridge. The medicament suspension or solution may then be dispensed in the usual manner, during which plunger 17 will pass the area previously occupied by membrane 15 and finally come into abutment with the inner face of diaphragm 19.

The preferred cartridge and needle assembly shown in Figs. 5 and 6 is adapted to be employed with a variety of hypodermic syringes, including the type illustrated in Fig. l or 3. The cartridge unit consists of an elongated, hollow glass vial or cylinder 11 containing a frangible membrane 15, as in the cartridge of Figs. 1 and 3. One end of the cartridge is closed by means of a reciprocable plunger 17, preferably of the type previously described, forming a hermetic seal with the internal wall of the glass cylinder. The other end of the cylinder includes an opening 40 which is sealed by means of a stopper member 43. The stopper is preferably formed of a re silient elastomeric material, such as rubber, and includes an external radially directed flange 45 for overlapping the Wall separating the needle from the contents .of the cartridge.

A-closure cap or hermetical seal member 21 isprovided,

as inthe cartridge of Figs. 1 and 3, to overlie the face of stopperflange 45 and to compress :the same against neck 47 as by crimping the closure cap behind the annular neck of the vial in thetmanner-indicated. The ferrule includes a central aperture which is adapted'to be aligned with the recess 49 in the face of stopper 43.

The needle unit comprises a needle holder formed as a stepped cylinder member having an axially extending sleeve-like flange or skirt 51, a cylindrical portion 53, and a reduced cylindrical forward portion 55. The skirt 51.ispreferably molded of aresilient elastic material, such as polyethylene resin, while the remainder of the holder is preferably composed of a relatively hard material, such as metal. The metal portion of the holder may be atfixed to the skirt by a number of means, a preferred method being shown in Figs. 5 and 6. The axially directed sleeve 51 forms an annular skirt which is adapted to fit tightly over the ferrule 21 of the cartridge unit in sealing relationship therewith, and for which purpose the sleeve 51 must include some radial play in order to provide a firm frictional fit and yet be able to slide over the ferrule. If desired, the peripheral portion of the sleeve may be slightly flared outwardly to facilitate assembly over the ferruleZZl.

The needle holder is adapted to integrally carry a hollow hypodermic needle or cannula 59 which for this purpose includes a central perforation or passageway 61in which theneedle 59 can be embedded in any knownmanner, as for example, by staking or soldering the needle unit with needle 59 in position, or by heat treating at least a portion of the metal area of the holder in the region of passageway 61 to shrink-fit or bind the same to the needle. A plug 65 is provided within hollow cylindrical portion 53 of the holder, preferably in frictional engagement with the interior of the holder although the plug may be affixed in any other suitable manner known in the art. Plug 65 advantageously has a stepped cylindrical configuration, forming a radially directed 'fiange-liketportion oand a body portion .68. This construction facilitates assembly and secure attachment of skirt portion 51 to cylindricalportion 53 of the needle holder asshown. The plug has a centralpassage 7t whichcarriesa sharpened stopper piercing needle 6'? for the purpose of penetrating the thin wall of thestopper separating the needle from the contents of the cartridge. If desired, :the :inner or stopper-piercing end of needle 67 may advantageously be bent so that the piercing point of the needle is spaced radially inwardly from the outer periphery of the main needle body and the side walls of the stopper recess 49. This facilitates more rapid assembly of the needle onto the cartridge unit during manufacture.

The inner face of plug 65 is provided with a filter 63 securely fastened thereto by crimping or rolling the body portion 68 against the filter, thereby forcing it into abutment with an annular face in body portion 68 as shown. Filter 63 may advantageously take the form of a screen, as previously described, for effectively removing any glass particles from the stream of medicament which is to pass through needle 59. Alternatively, filter 63 may be secured within cylindrical portion 53 of the needle holder.

Needle cover 69 is firmly mounted on the reduced cylindrical portion 55 but is releaseably secured thereto by means of a tight but manually movable fit, the cover 69 being adapted to be slipped off of the reduced portion by pulling it axially outwardly.

The operation of the cartridge needle assembly shown in Figs. 5 and 6 is as follows. The complete cartridge needle assembly, with membrance 15 separating the medicament from the diluent, is inserted into a hypodermic syringe such as that shown in Fig. 5. Moving the cartridge forward within the casing of the syringe causes the annular step of skirt 51 to come into abutment with end .wall as of the syringe casing 1. Continued axial movement of the cartridge in the same directionresults in penetration of stopper 43 by the stopper piercingneedle 67. Plunger rod 7 is, of course, firmly secured to reciprocable plunger ll? in any suitable manner'andtthe device is then preferably held in a vertical position zwith the needle end pointed upwardly. The exertion.:0.f pres sure on the thumb piece 8 causes membrane 15 to become ruptured, thereby permitting the contents of the two compartments normally separated by the membrane to come into communication with one another. The resulting mixture is then thoroughly shaken, preferably with the device still in an inverted position. This prevents the contents of the cartridge from being expelledthrough the needle while mixing is taking place. Any air contained in the cartridge is readily expelled by further advancing' plunger 17; the device is then inreadiness for-an injection, which may take place in the usual manner, filter 63 effectively retaining any glass particles which may pass through needle 67.

In still another embodiment of this invention, a modified form of stopper is provided to effectively filter any glass particles from the stream of medicament which .is to pass through the needle during injection. Onesuch stopper is shown in Fig. 7 while another is shown inFig. 8. in both instances an ordinary hypodermic needle or one which does not contain a filter, may be employed.

With reference to Fig. 7, the stopper is composedof a cylindrical or plug like portion 71 which is received by the reducedcylindrical neck of the vial or-cartridge, and a flanged portion 73 which is adapted to be securely afiixed to the neck of the vial by suitable means, such as the closure cap previously described. This stopper carries a central axially directed recess 75 forming a thin wall portion 77 normally separating the needle from the contents of the cartridge. The inner end of the stopper is provided with a filter or screen 79 affixed thereto, as by crimping or the like. It may also be molded or cemented to the stopper, but frictional attachment is adequate for most purposes. In the stopper shown in Fig. 8, a filter till is incorporated within recess 75 during molding and firmly retained therein. In both of these embodiments, the stopper piercing end of the needle maybe passed through the thin wall portion 77 either before or after mixing of the ingredients within the cartridge, terminating within recess '75 Without contacting filters 79 or 86. A cartridgeor syringe constructed with such stoppers may be operated in the manner previously described.

While a single filter is effective for most purposes, in certain circumstances it may be desirable to employ more than one filter. This may be accomplished by employing more than one screen in each of the structures described. A filter-carrying stopper may also be employed with a needle containing a filter in the manner shown, thereby providing a double filter, one in the stopper and one in the needle. However, this is generally unnecessary if a filter of the proper size is selected.

As many other apparently different embodiments of this invention may be made without departing from the spirit and scope hereof, it is to be understood that this invention is not limited, except as defined in the appended claims.

What is claimed is:

1. A hypodermic syringe comprising a cylindrical cartridge provided with a frangible membrane dividing said cartridge into two compartments, a slidable plunger at one end of said cartridge adapted to operate against a body of liquid within said cartridge between said plunger and said membrane and thereby rupture the same, a perforable seal at the other end of said cartridge for receiving a hypodermic needle, and a filter separating the contents of said cartridge from the point of discharge therefrom for effectively preventing the ejection of particles resulting from rupture of said frangible membrane.

2. A hypodermic syringe comprising a cylindrical cartridge provided with a frangible disk-like membrane dividing said cartridge into two compartments, a slidable plunger at one end of said cartridge adapted to operate against a body of liquid within said cartridge between said plunger and said membrane and thereby rupture the same under normal operating pressures, said plunger having a stroke which traverses the situs of said membrane and being provided with at least three circumferential ribs extending about its outer periphery, a perforable seal at the other end of said cartridge for receiving a hypodermic needle and a filter separating the contents of the cartridge from the point of discharge therefrom for eiiectively preventing the ejection of particles resulting from rupture of said membrane.

3. A hypodermic syringe comprising a cylindrical cartridge provided with a frangible disk-like membrane dividing said cartridge into two compartments, a s'lidable plunger at one end of said cartridge adapted to operate against a body of liquid Within said cartridge between said plunger and said membrane and thereby rupture the same, said membrane being of such thickness as to rupture at substantially the point of juncture between said membrane and the side walls of said cartridgewhen ordinary operating pressures are exerted against said plunger, said plunger having a stroke which traverses the situs of said membrane and being provided with at least three circumferential ribs extending about its outer periphery for maintaining an edective seal as the sitns of said membrane is traversed, a perforable seal at the other end of said cartridge for receiving a hypodermic needle, and a hypodermic needle in operative engagement with said seal, said needle being provided with a filter therewithin for effectively preventing the discharge of particles resulting from rupture of said membrane.

4. A hypodermic syringe comprising a cylindrical cartridge provided with a frangible disk-like membrane dividing said cartridge into two compartments, a slidable plunger at one end of said cartridge adapted to operate against a body of liquid within said cartridge between said plunger and said membrane and thereby'rupture the same, said membrane being of such thickness as to rupture at substantially the point of juncture between said membrane and the side walls of said cartridge when ordinary operating pressures are exerted against said plunger, said plunger having a stroke which traverses the situs of said membrane and being provided with at least three circumferential ribs extending about its outer periphery for maintaining an effective seal as the situs of said membrane is traversed, and a perforable seal at the other end of said cartridge for receiving a hypodermic needle.

5.'A hypodermic syringe needle comprising a hollow cylindrical hub provided at one end with a tissue piercing needle connecting thereinto, a plug within the other end of said hub provided with a cartridge piercing needle con necting thereinto, and a filter within said hub separating said tissue piercing needle from said cartridge piercing needle to efiectively screen all medicament before passage through said tissue piercing needle.

6. A hypodermic needle comprising a hollow cylindrical hub provided at one end with a tissue piercing needle connecting thereinto, a hollow cylindrical plug within the other end of said hub and provided with a radially directed flange extending about the annular end of said hub, an axially extending cylindrical skirt having an annular end Wall retained by said flange in abutment with the annular end of said hub, said skirt being adapted for slidable engagement about a hypodermic syringe cartridge, a cartridge piercing hypodermic needle carried by said plug and connecting into said hollow hub, the inside of said plug being provided with a filter for screening all medicament before passage thereof through said tissue piercing needle.

7. A stopper for a hypodermic syringe cartridge comprising a hollow cylindrical plug portion and aradially directed flange portion, said plug portion being provided with an axially extending inner recess terminating in the region of said flange portion and forming a relatively thin barrier separating said recess from the outer periphery of the stopper for receiving the stopper piercing end of a hypodermic syringe needle, and a screen extending across said recess at a distance from said barrier sufficient to afford unobstructed communication between the stopper piercing end of a hypodermic syringe needle and said recess.

References Cited in the file of this patent UNITED STATES PATENTS 1,943,120 Kabnick Jan. 9, 1934 1,987,146 Hein Jan. 8, 1935 2,377,274 Smith May 29, 1945 2,470,298 Fields May 17, 1949 2,705,956 McLaughlin Apr. 12, 1955 FOREIGN PATENTS 407,559 Great Britain Mar. 22, 1934 

